Aquatic and swamp plant communities as indicators of habitat properties of astatic water bodies in north-eastern Poland

Phytosociological and habitat studies were conducted on the water and swamp vegetation of astatic water bodies within north-eastern Poland. The phytocoenoses were selected on the basis of dominance of species forming the particular communities. The analysis of 147 relevés showed the existence of 10 vegetation types: Lemnetum minoris, Spirodeletum polyrrhizae, Riccietum fluitantis, Elodeetum canadensis, Polygonetum natantis, Typhetum latifoliae, Caricetum elatae, Calletum palustris, Potentilletum palustris, Menyanthetum trifoliatae. Among the properties of water analysed water depth, , pH, total and carbonate hardness, PO₄³⁻, Ca²⁺, Mg²⁺ and Na⁺ were found to be most important in differentiating the habitats of the vegetation types studied. Substrate properties, which best differentiated the habitats of the associations studied were NO₃⁻, Na⁺, water content, pH and total N. In spite of the wide variability of habitat conditions occurring in astatic water bodies, particular phytocoenoses distinguished on the basis of dominance of one species were associated with specific habitats. The particular phytocoenoses or groups of phytocoenoses could be good indicators of various habitat conditions that occur within astatic water bodies or changes taking place in these habitats.     

SH waves in a layer with temperature dependent properties

The paper deals with the problem of SH harmonic wave propagation in an elastic layer with temperature dependent properties. The shear modulus and mass density are linearly dependent on temperature. The layer is rested on a rigid foundation and the upper boundary is free of loadings. The boundary planes are kept at different constant temperatures. The wave velocity and amplitude of stresses are analysed.     

Drought and its effects on spring discharge regimes in Poland and Germany during the 2015 drought

Areas of Western and Central Europe were severely affected by devastating droughts in 2003 and 2015. A sharp decrease in annual atmospheric precipitation led to diminished spring discharges. Analysis of the fluctuations in discharge from three groups of springs in the south of Poland, namely in the Sudetes and Carpathian mountains, and in the German province of Bavaria revealed an average discharge reduction ranging from 52 to 4%. The study proved the existence of a relationship between diminished groundwater recharge from precipitation and the type of rock forming the reservoir as well as the parameters of the rock in the drained catchment. Spring discharge regime was compared for various periods to show that a decline in the regime correlates with a decline in river flow rate; considering the continually changing weather patterns, this correlation is arguably a key factor in sustainable water management.     

Refined timing and kinematics for Baltica–Avalonia convergence based on the sedimentary record of a foreland basin

The Caledonian foreland basin of Poland onlaps the SW slope of the East European Craton and is elongated in a NW–SW direction along the margin of the Baltica palaeocontinent. The base of the synorogenic clastic wedge rises in age from Llandovery to Ludlow between NW and SE Poland, respectively. As the initial influx of orogen‐derived detritus can be unequivocally identified, this diachronism documents a southeastward migration of the basin depocentre, parallel to the present‐day Caledonian Deformation Front. Our best‐fit plate model shows an oblique collision of Baltica and Avalonia, the latter initially indenting the Baltica margin in the NW. Afterwards, Baltica was progressively underthrust beneath Avalonia towards the SE in response to the oblique soft‐mode closure of the Tornquist Ocean. The final deformation event within the Caledonian foreland took place in the earliest Devonian as a far‐field effect of sinistral orogen‐parallel displacements along the Iapetus suture.     

Deep Electrical Resistivity Structure of the European Lithosphere in Poland Derived from 3-D Inversion of Magnetotelluric Data

Surveys in Geophysics - This paper presents a three-dimensional (3-D) model of the resistivity distribution in the European lithosphere at the junction between the East European Craton, the...     

The Tepla(?)/Saxothuringian suture in the Karkonosze–Izera massif, western Sudetes, central European Variscides

The southern and eastern Karkonosze-Izera massif (northern Bohemian Massif) exposes blueschist facies rocks and MORB-type magmatic complexes. During Late Devonian to Early Carboniferous times, these were overthrust within a nappe pile toward the NW onto the pre-Variscan Saxothuringian basement composed of the Izera-Kowary metagranitoids and their envelope. The lowermost nappe (or parautochthonous?) unit of the pile is the low-grade metamorphosed Jewt3d complex, comprising a Devonian to Early Carboniferous sedimentary succession of the Saxothuringian passive margin. This is tectonically overlain by the South Karkonosze complex, which represents Ordovician-Silurian volcano-sedimentary infill of the Saxothuringian basin, affected by Late Devonian HP metamorphism. The uppermost nappe is the Early Palaeozoic epidote-amphibolite grade Leszczyniec MORB-like complex, cropping out on the eastern margin of the Karkonosze-Izera massif. It probably represents a fragment of obducted Saxothuringian basin floor. The nappe pile was stacked beneath the overriding upper plate margin, now concealed below the Intra-Sudetic basin and hypothesized to represent a fragment of the Tepla-Barrandian terrane. The nappe stacking, triggered by buoyancy-controlled upward extrusion of the subducted continental slab, was the main mechanism for the exhumation of HP rocks. The final stages of the NW-ward nappe stacking were accompanied and followed by SE-directed Early Carboniferous extensional collapse. The lower plate of the suture zone was uplifted at that time and intruded by the ~330-Ma-old, nearly undeformed Karkonosze granite pluton. As a result of the collapse, the Tepla-Barrandian(?) upper plate was downthrown on shear zones and brittle faults and buried under several km-thick synorogenic Late Tournaisian(?) through Namurian and post-orogenic Late Carboniferous-Early Permian succession of the Intra-Sudetic basin. The south and east Karkonosze suture most probably is a fragment of the Tepla/Saxothuringian (Münchberg-Tepla) suture belt known from the western Bohemian Massif.     

Normal form,Lie-Poisson structure and reduction for the Henon-Heiles system

The reduced Henon-Heiles system is investigated as a Hamiltonian dynamical system obtained by applying the normalization of the HamiltonianH=1/2(p ₁ ² +p ₂ ² +q ₁ ² +q ₂ ² )+1/3q ₁ ³ –q ₁ q ₂ ² to fourth-degree terms. The related equations of motion are bi-Hamiltonian and possess the Lie-Poisson structure. Each Lie-Poisson structure possesses an associated Casimir function. When reduced to level sets of these functions, the equations of motion take various symplectic forms. The various reductions give different coordinate representations of the solutions. These coordinate representations are used to seek the simplest representation of the solutions.